Speaker: Prof. Jay Fineberg
Host: Dr. Itamar Kolvin
Title: The Fundamental Physics of the Onset of Frictional Motion: How does friction (or an Earthquake) start?
Abstract:
When two bodies are in contact, they are separated by an interface of sparse contacts. For the bodies’ motion (frictional motion) to initiate, these contacts have to be detached. We first show that this detachment process takes place by means of rapid singular cracks that propagate, at nearly sound speeds, within the interface. These cracks are akin to the earthquakes that enable contacting tectonic plates to slide. Their singular form, dynamics and arrest are well-described by the theory of fracture. We then describe how these rapid crack (earthquakes) are first formed; frictional motion starts via extremely slow, aseismic, nucleation fronts. We will then briefly develop a new theoretical description of this nucleation process that extends fracture mechanics. This theory quantitatively describes all experimentally observed features of the nucleation process and merges seamlessly with the accepted fracture mechanics description of rapid dynamic cracks. These results provide new understanding of the physics of friction, earthquake dynamics and even the more general question of ‘how things break’.
Reference:
[1] S. Gvirtzman, S., D. S. Kammer, M. Adda-Bedia, J. Fineberg. Nature 637, 369–374 (2025). https://doi.org/10.1038/s41586-024-08287-y.
Event Details
Date/Time:
-
Date:Tuesday, October 14, 2025 - 2:30pm to 3:45pm
Location:
Howey N201/N202
